code: def test_dump_file(self):
      this_file = os.path.splitext(__file__)[0] + ".py"
      f = open(this_file)
      try:
          numlines = len(f.readlines())
      finally:
          f.close()
  
      dump_file(this_file, "I am the header")
      self.assertEqual(len(self._logs), numlines + 1)
  
file_path: catboost/contrib/tools/python/src/Lib/distutils/tests/test_config_cmd.py
imports: import unittest
  import os
  import sys
  from test.test_support import run_unittest
  from distutils.command.config import dump_file, config
  from distutils.tests import support
  from distutils import log
label_desc: Use image node_id 4 for calling the ConfigTestCase obj's underlying member method code with example usage: obj.test_dump_file() without return types